<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <script src="../js/vue.js"></script>
    </head>
    <body>
        <div id="app">
            <input type="text" v-focus="true">
        </div>
        <script>
            Vue.directive('focus',{
                inserted (el,binding) {
                    console.log('元素被插入');
                    console.log(binding);
                    if (binding.value) {
                        el.focus()
                    }
                }
            })
            var vm  = new Vue({
                el:'#app'
            })
        </script>
    </body>
</html>